Micro-morphological feature visualization, auto-classification, and evolution quantitative analysis of tumors by using SR-PCT.

Tissue micro-morphological abnormalities and interrelated quantitative data can provide immediate evidences for tumorigenesis and metastasis in microenvironment. However, the multiscale three-dimensional nondestructive pathological visualization, measurement, and quantitative analysis are still a challenging for the medical imaging and diagnosis. In this work, we employed the synchrotron-based X-ray phase-contrast tomography (SR-PCT) combined with phase-and-attenuation duality phase retrieval to reconstruct and extract the volumetric inner-structural characteristics of tumors in digesting system, helpful for tumor typing and statistic calculation of different tumor specimens.

High-resolution quantitative phase imaging based on a spatial light modulator and incremental binary random sampling.

We propose a single-beam high-resolution quantitative phase imaging method based on a spatial light modulator (SLM) and an incremental binary random sampling (IBRS) algorithm. In this method, the image of the test object presents on the image sensor through an optical microscopy system composed of an objective lens and a collimating lens. A transmittance SLM displaying a group of well-designed IBRS patterns is inserted in the optical microscopy system to modulate the object wavefront.

Tri-arm multipinhole interferometer for wavefront measurement and diffractive imaging.

We propose a tri-arm (or Y-shaped) multipinhole (MP) interferometer for wavefront measurement based on a specially designed tri-arm MP plate. We demonstrate that the complex amplitude of a wavefront sampled by the tri-arm MP plate inserted between the object and the detector plane can be extracted directly from the Fourier transform of a far-field diffraction intensity pattern without the need for any iterative algorithm. A form of coherent diffractive imaging based on a rotatable tri-arm MP plate is also demonstrated, which provides a feasible approach for lensless diffractive imaging in real time.

Diffractive imaging based on a multipinhole plate.

We report on a noniterative method for coherent diffractive imaging based on a specially designed multipinhole (MP) plate. We demonstrated that the complex amplitude of the wavefront penetrating through an MP plate inserted between the specimen and the detector plane can be directly extracted from the Fourier transform of a single far-field diffraction intensity pattern without need of any iterative algorithm. A form of scanning diffractive imaging based on a rotatable MP plate is also demonstrated, which provides a feasible approach for lensless diffractive imaging of complex-valued objects.

Laplacian differential reconstruction of in-line holograms recorded at two different distances.

We analyze the diffraction of the picture obtained by the subtraction of two in-line holograms recorded in two planes at distances of z and z+Deltaz apart from the object plane. Our theoretical analysis reveals that the reconstructed field at the object plane is approximately equal to the Laplacian second-order differentiation of the object wave in transverse direction when Deltaz is much smaller than the distance z, that is, the reconstructed image presents a high quality of edge enhancement. We further investigate the dependence of the edge-enhancement quality on the longitudinal differential distance Deltaz and find that the reconstructed images have the sharpest edge-enhancement and high signal-to-noise ratio at the same time only when the value of Deltaz/z lies between 0.

Phase contrast Talbot array illuminators.

We propose a method for designing an improved phase-only Talbot array illuminator, called a phase contrast Talbot array illuminator (PCTAI), which could be used to generate an array of spots with a special intensity structure and high efficiency. As examples, we designed two types of PCTAIs for generating an array of line and hollow spots, respectively. Some experimental results revealing the phase contrast effect and demonstrating the feasibility of the PCTAIs are also given.